EBER-RISH and CD20 staining of PBMNCs obtained from PTLD patient no. 1 and a healthy EBV⁺ donor.

(A) EBER-RISH shows numerous EBV⁺ B cells (indicated by arrows) in the peripheral blood of PTLD patient no. 1 at the period of the third PTLD diagnosis. Insert shows closeup of EBER and CD20⁺ cell. (B) In the healthy donor, there was no EBER signal detected, thereby confirming the low EBV loads in peripheral blood of healthy individuals.